Absent a suitable dispersant, hydrophobic (e.g., grime, oil, soot) and hydrophilic (e.g. clay) soil which is removed during the washing step of the laundry process can re-deposit onto the cleaned fabric. Soil dispersants act by sequestering dirt once it is dissolved or dispersed in the laundry liquor and keeps the suspended soil in the laundry liquor where it can be carried away during the normal rinsing process.
Typically, if bleaching agents are present, especially peroxygen bleaches which are formulated into both liquid and granular laundry detergent compositions, the formulator must consider the instability of a particular soil dispersant toward bleach. Many successful dispersants have polyalkyleneamine or polyalkyleneimine backbones which are susceptible to oxidation at the amine functionalities and potentially to breakdown or fragmentation by bleaching agents which may be present. From another view, the interaction of bleaching agents with these polyalkyleneimine-based dispersants depletes the amount of bleach present therefore affecting the bleaching performance.
Accordingly, there remains a need in the art for bleach compatible, highly effective hydrophobic soil dispersants. Surprisingly, it has been found that certain higher molecular weight polyalkyleneimines when highly alkoxylated, are compatible with bleach in laundry compositions and additionally provide hydrophobic soil dispersion. It has also been found that it can be beneficial that the alkoxylated dispersants comprise in the alkylene oxide substituant group mixtures of ethylene oxide and propylene oxide.